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Accelerator Needs from High Energy Physics for the next 50 years -- or -- 50 years in 15 minutes + questions. will concentrate on two main questions: -- neutrinos -- high energy exploration Both saw revolutions in 2011-2012.
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Accelerator Needs from High Energy Physics for the next 50 years -- or -- 50 years in 15 minutes + questions will concentrate on two main questions: -- neutrinos -- high energy exploration Both saw revolutions in 2011-2012
Massive neutrinos: THE NEW PHYSICS there is neutrino masses constitute a new question which has no unique answer in the Standard Model -- while all othercharged fermions receive ‘Dirac’ masses neutrinos are neutral and couldalsoreceive ‘Majorana’ masses whichalllow a transition between neutrinos and antineutrinos i.e. matter and anti-matter As a consequence, massive neutrinos couldquitenaturallyhave ‘sterile’ brothers … and contribute to the solution of severalwellknown observations None of which have an explanationwithin the Standard Model. -- baryon asymmetry of the universe (CP asymmetry) -- darkmatter (sterile neutrinos) -- and couldcontribute for a fraction of an additionaldegree of freedom in the earlyuniverse (CMB, Plank) depending on their mass.
Neutrinos : the New Physicsthereis… and a lot of it! Mass hierarchies are all unknownexcept m1 < m2 Preferred scenario has both Dirac and Majoranaterms … … a bonanza of extremeexperimental challenges
Atmospheric neutrinos |Dm232| =| m23-m22| , 23. Solar neutrinos (SNO) reactor (KAMLAND) Dm221 = m22-m21 , 12 Accelerator (T2K (06/2011, MINOS 07/2011) 13 and rectors (DChooz12/2011, DayaBay 03/2012, Reno 04/2012) 1998 2002 2011-12 NOW Do neutrinos follow the same mass hierarchy as all other fermions? Do ’s and ‘s oscillate the same? (CP violation) Do neutrinos have a Majorana mass term? Do sterile neutrinos exist? What are their masses (active and sterile)? (anywhere from ~eV to ~1019eV!) sign( Dm232) CP 0 0 Precisionmeasts of all the above, new oscillations or new neutralobjectsthatinteractonly withgravity. except for smallmixing with active ’s Time (Yrs) 5-10 10-20 10-20 10-40 50?
Alain Blondel HIF Workshop 30-11-2011 EURO DESIGN STUDY superbeam (pion decay) Neutrino Factory (muon decay) Beta-beam rad-ion decay
Neutrino CP asymmetry Probably requires combination of -- a high statistics conventional beam (horn focused superbeam) e.g. CERN Pyhasalmi, T2HK, Fermilab to DUSEL, ESS to ? -- a precision cross-section experiment -- eventually a facility that combines the two: neutrino factory
MICE Collaboration across the planet Coupling Coils 1&2 Focus coils Spectrometer solenoid 2 Spectrometer solenoid 1 RF cavities RF power Beam PID TOF 0, TOF 1 Cherenkovs Downstream particle ID: TOF 2, KL EMR VariableDiffuser Liquid Hydrogen absorbers 1,2,3 Incoming muon beam Trackers 1 & 2
High statistics = High beam power * high detector mass 2-4MW >50-100kton Get the beam power where it is -- why not the 5MW ESS? (Ekelof, Dracos) -- make a neutrino superbeam as in EUROnu Get the Large Underground neutrino detector -- why not one of LAGUNA options? accumulator Garpenberg 540 km target/horn station ESS Helium cooled ball target 4-horn neutrino beam CERN 10 June 2013 M. Dracos
vSTORM: neutrinos from stored muons first step towards neutrino factory and muon collider Clean solution of LSND ‘sterile neutrino’ Precision measurements of cross-sections (E=0.5-3 GeV) Proposal at Fermilab last week and at CERN 25 June
1. Scalar boson H(126) has been discovered! 2. LHC detectors have donemuchbetterthanprojected hereis a plot from ATLAS in 2005, expected 3-4with 10fb-1 at 14TeV
The LHC is a Higgs Factory ! 1M Higgs already produced – more than most other Higgs factory projects. 15 Higgs bosons / minute – and more to come (gain factor 3 going to 13 TeV) Difficulties: several production mechanisms to disentangle and significant systematics in the production cross-sections prod. Challenge will be to reduce systematics by measuring related processes. if observed prod (gHi )2(gHf)2 extract couplings to anything you can see or produce from H if i=f as in WZ with H ZZ absolute normalization
c) The discovery of the Higgs boson is the start of a major programme of work to measure this particle’s properties with the highest possible precision for testing the validity of the Standard Model and to search for further new physics at the energy frontier. The LHC is in a unique position to pursue this programme. No measurement gHcc and GH Assume no exotic Scalar decays ? ? ? In bold, theory uncertainty are assumed to be divided by a factor 2, experimental uncertainties are assumed to scale with 1/√L, and analysis performance are assumed to be identical as today • Couplingmeasurementswithprecision : • in the range 6-15% with LHC - 300 fb-1 • in the range 1-4%with HL-LHC - 3000 fb-1 HL-LHC (3 ab-1 at 14 TeV): Highest-priority recommendation from European Strategy B. Mele
t H Full HL-LHC Z W b • Couplingmeasurementswithprecision : • in the range 6-15% with LHC - 300 fb-1 • in the range 1-4%with HL-LHC - 3000 fb-1 B. Mele
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m+m-Collider as Higgs Factory , W, … • A m+m-collider can do things that an e+e- collider cannot do • Direct coupling to H expected to be larger by a factor mm/me • ,jh [speak = 70 pb at tree level] • Can it be built + beam energy spread dE/E be reduced to 3×10-5 ? • 4D+6D Cooling needed! • For dE/E = 0.003% (dE ~ 3.6 MeV, GH ~ 4 MeV) • no beamstrahlung, reduced bremsstrahlung • Corresponding luminosity ~ 1031-32 cm-2s-1 • Expect 2300-23000 Higgs events in 100 pb-1/ year • Using g-2 precession, beam energy and energy spectrum • Can be measured with exquisite precision (<10 keV) • From the electrons of muon decays • Then measure the detailed lineshape of the Higgs at √s ~ mH • Five-point scan, 50 + 100 + 200 + 100 + 50 pb-1 • Precision from H→bb and WW : , W, … s (pb) As will be seen e+e- collider can probably do the job for the H(126), but the muon collider remains the best road to high energy lepton collisions (E~>2-5 TeV) √s s(mH), TLEP
Higgs Production Mechanism in e+ e- collisions H(126) is produced by the “higgstrahlung” process close to threshold Production xsection has a maximum at near threshold ~200 fb 1034/cm2/s 20’000 HZ events per year. e- H Z – tagging by missing mass a beam of Higgs bosons Precision 1M events 5 years * 1035/cm2/s Sensitivity to exotic/invisible decays (darkmatter?) Z* Z e+ For a Higgs of 125GeV, a centre of mass energy of 240GeV is sufficient kinematical constraint near threshold for high precision in mass, width, selection purity
Performance of e+ e- colliders TLEP : Instantaneous lumi at each IP (for 4 IP’s) Instantaneous lumi summed over 4 IP’s Z, 2.1036 WW, 6.1035 HZ, 2.1035 tt , 5.1034 Physics case for linear colliders: higher energy! deviation comes up in 13 TeV LHC data and if LC is needed to investigate it further. R. Aleksan Physics case for circular colliders Measure precisely (e.g. masses to fraction of MeV) known particles (TeraZ, OkuW, MegaH and tops) to see evidence for new phenomena.
Higgs factory performances Precision on couplings, cross sections, mass, width, … Summary of the ICFA HF2012 workshop (FNAL, Nov. 2012) arxiv1302:3318 • Best • precision HL-LHC ~ as good as LCs
How can one increase over LEP 2 (average) luminosity by a factor 500 without exploding the power bill? Answer is in the B-factory design: a very low vertical emittance ring with higher intrinsic luminosity and a small value of y* electrons and positrons have a much higher chance of interacting much shorter lifetime (few minutes) feed beam continuously with a ancillary accelerator Storage ring has separatebeam pipes for e+ and e- for multibunchoperation Going to evenhigherluminositieswith charge compensation?
80 km ring in KEK area 12.7 km KEK
105 km tunnel near FNAL (+ FNAL plan B from R. Talman) H. Piekarz, “… and … path to the future of high energy particle physics,” JINST 4, P08007 (2009)
What is a (CHF + SppC) China Higgs Factory (CHF) Circular Higgs factory (phase I) + super pp collider (phase II) in the same tunnel pp collider ee+ Higgs Factory HF2012
prefeasibility assessment for an 80km project at CERN John Osborne and Caroline Waiijer ESPP contr. 165 TLEP + VHE/LHC (100 TeV)= LONG TERM VISION FOR CERN!
tentative time line Zimmermann, Rossi, Aleksan etc… 1980 2000 2010 1990 2030 2020 2040 Design, R&D LHC Constr. Physics Proto. Design, R&D HL-LHC Constr. Physics Design, R&D TLEP Physics Constr. Design, R&D Constr. Physics VHE-LHC
At the moment we do not know whatis the most sensible scenario LHC offered 3 possible scenarios: (could not lose) Discover that there is nothing in this energy range. This would have been a great surprise and a great discovery! • Discover SM Higgs Boson • and thatnothingelse • iswithinreach • Most Standard scenario • greatdiscovery! Discover many new effects or particles great discovery! Keeplooking in 13/14 TeV data! NO But…. So far we are here Also: understand scaling of LHC errors with luminosity Answer in 2018 High precision High energy BE PREPARED!
Conclusions and outlook (my own view)Particle physics with accelertors for the next 50 years The last two years have seen two major discoveries in particle physics The discovery of large 13e transitions (T2K, Daya Bay) -- opens the way for a long term future in neutrino physics Mass hierarchy, CP violation, sterile neutrino search in a wide mass range. -- intense and precise neutrino sources will be required Superbeam, vSTORM, (possibly) Neutrino Factory, etc… 50 Years of neutrino experiments to come! The discovery of the H(126) scalar boson opens the way to precise investigations -- HL-LHC -- a lepton collider of sufficient luminosity -- best performance with an e+e- circular machine TLEP in a large (80km) tunnel that could pave the way to a Very Large Hadron Collider (100 TeV) -- but is limited in energy reach -- recommend choice vs LC when LHC results at 13 TeV available 2017-18 in 2035 the LEP/LHC tunnel will have been used for 46 years…. the TLEP/VHE-LHC tunnel would be used for > 50 years! Accelerator R&D is more than ever crucial to keep options open, keeping an open mind that final choice of project will depend on physics arguments and circumstances
Sterile neutrino search a global view: Detected by mixing between sterile and active neutrino ideal experiments: source detector active, knownprocess knownprocess 1. disappearance, not necessarily oscillatory best is NC disappearance sterile if sterile cannot be produced (too heavy) apparent deficit in decay rate Heavy flavourdecays… couldevenbe Z or H invisible width (high energyresearch) active, 2. appearance (at higher order) Thesewillbeprecisionexperiments -- high intensity (protons, targets) -- preciselyknown flux (neutrino factories) -- all energiesconcerned Alain Blondel NUFACT12 23-07- 2012
Recommendation from European Strategy (2) • High-priority large-scale scientific activities • Second-highest priority, recommendation #2 • Excerpt from the CERN Council deliberation document (22-Mar-2013) d) To stay at the forefront of particle physics, Europe needs to be in a position to propose an ambitious post-LHC accelerator project at CERN by the time of the next Strategy update, when physics results from the LHC running at 14 TeV will be available. CERN should undertake design studies for accelerator projects in a global context, with emphasis on proton-proton and electron-positron high-energy frontier machines.These design studies should be coupled to a vigorous accelerator R&D programme, including high-field magnets and high-gradient accelerating structures, in collaboration with national institutes, laboratories and universities worldwide. The two most promising lines of development towards the new high energyfrontier after the LHC are proton-proton and electron-positron colliders. Focused design studies are required in both fields, together with vigorous accelerator R&D supported by adequate resources and driven by collaborations involving CERN and national institutes, universities and laboratories worldwide. The Compact Linear Collider (CLIC) is an electron-positron machine based on a novel two-beam acceleration technique, which could, in stages, reach a centre-of-mass energy up to 3 TeV. A Conceptual Design Report for CLIC has already been prepared. Possible proton-proton machines of higher energy than the LHC include HE-LHC, roughly doubling the centre-of-mass energy in the present tunnel, and VHE-LHC, aimed at reaching up to 100 TeV in a new circular 80km tunnel. A large tunnel such as this could also host a circular e+e-machine (TLEP) reaching energies up to 350 GeV with high luminosity. Brussels, 29-31 May 2013
Design Studyisnowstarting ! Visithttp://tlep.web.cern.ch and suscribe for work, informations, newsletter Global collaboration: collaboratorsfrom Europe, US, Japan, China Nextevents: TLEP workshops 25-26 July 2013, Fermilab 16-18 October, CERN Joint VHE-LHC+ TLEP kick-off meeting in February 2014
The first 200 subscribers: Janot The distribution of the country of origin reflects the youth of the TLEP project and the very different levels of awareness in the different countries. The audience is remarkably well balanced between Accelerator, Experiment, and Phenomenology -- the agreement with the three colour model is too good to be a statistical fluctuation!
Conveners at interim. Janot J.Ellis Zimmermann